1. Field of the Invention
The present invention relates to an image processing apparatus, a control method therefor, and a computer-readable storage medium storing a program for implementing the method, and in particular to a secure print technique of the image processing apparatus.
2. Description of the Related Art
Conventionally, a secure print function of an image forming apparatus is to maintain confidentiality by preventing a third party from seeing printed matter input to an image processing apparatus from an information processing apparatus connected to a LAN.
A brief explanation of the secure print function will now be given in terms of user's perspective.
A user inputs a print job with a password added thereto from an information processing apparatus to an image processing apparatus via a LAN. After inputting the job, the user moves to the image processing apparatus and enters a password through an operation unit of the image processing apparatus. After authentication is completed, printing is started, and as a result, the user can properly obtain a printing result. For example, according to Japanese Laid-Open Patent Publication (Kokai) No. 2006-293933, internal processing by an image processing apparatus temporarily accumulates image data, which is generated by carrying out PDL interpretation and rendering on a received print job, in a storage device such as an HDD. After a rendering process for all pages of input data is completed, the image processing apparatus brings the job into a state of waiting for authentication. The image processing apparatus accepts an input of a password via the operation unit, and after authentication, starts a printing process on the image data accumulated in the storage device.
In recent years, there have been inexpensive image processing apparatuses having only low-capacity storage devices, and there has been a great demand for equipping these image processing apparatuses as well with the secure print function.
However, the conventional methods are based on the assumption that an image processing apparatus has a high-capacity storage device such as an HDD, and when they are applied to an image processing apparatus having a low-capacity storage device, problems will arise.
Also, according to prior arts relating to problems involved in low-capacity secure print, other problems will arise.
A description will now be given of the conventional methods and the problems involved in low-capacity secure print.
First, a description will be given of a problem that will arise when the conventional methods are applied to an image processing apparatus having only a low-capacity storage device. The problem that will arise in this case is that in the image processing apparatus, there is a shortage of storage areas for image data that has been subjected to rendering, and there are jobs that cannot be printed. The amount of image data after rendering of a print job cannot be known until rendering is performed. For this reason, when the capacity becomes full after processing of a job is started, the image processing apparatus conventionally cancels the job for the purpose of protection. The problem of the capacity becoming full hardly arises on practical side in an image processing apparatus having a high-capacity storage device such as an HDD, but frequently arises in a low-capacity image processing apparatus that has no HDD or the like.
Next, a description will be given of problems involved in small-capacity secure print according the prior arts. Examples of the prior arts relating to problems involved in small-capacity secure print include Japanese Laid-Open Patent Publication (Kokai) No. 2006-293933. According to the prior arts, a job ticket including a password is used before a print job is received. An image processing apparatus receives a job ticket including a password from a host, and after performing authentication using the job ticket, starts receiving a print job as a main part of the job and carries out a rendering process and a printing process, thus realizing low-capacity secure print.
However, in this method according to the prior arts, because after authentication, an image processing apparatus receives a job and carries out all subsequent processes, there may be cases where a user has to wait from authentication to start of printing. For example, in the case of a job for which a fallback or the like occurs during rendering in an image processing apparatus, a user may have to wait for several minutes. In such a case, although the user is executing secure print for originals desired to be maintained confidential, an undesirable situation may occur in which printing is not started immediately after the user instructs authentication via an operation unit of the image processing apparatus. It should be noted that there is no such wait time according to a secure print method for conventional models having HDDs, because after completion of a rendering process on all pages of a print job, authentication is performed, and printing is started.